<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<script>
    const num1 = prompt("请输入第一个数")
    const num2 = prompt("请输入第二个数")
    alert(parseFloat(num1) + parseFloat(num2))
</script>
</body>
</html>